Overview objectives are known which are typically used in visual observation. They are generally corrected only for the visual spectrum and do not have high numerical apertures. Achromatic or semi-apochromatic objectives 5x/0.13 up to a maximum of 5x/0.25 are, for example, customary. Higher apertures lead to a higher resolving power and this cannot be resolved by the human eye. Likewise, good correction in the ultraviolet (UV) range or in the infrared (IR) range is not necessary, because the eye is blind in these ranges.
This situation is changing increasingly with the increasing trend towards digital microscopy. Digital microscopes are capable of resolving substantially more details than the human eye. This generally takes place with the aid of high-resolution cameras, or with the aid of optical secondary magnification systems. Also with regard to the usable wavelength spectrum digital imaging systems are advantageous. Due to these advantages by comparison with the human eye, even with the overview objectives there is a repeated requirement for high-aperture systems to be made available with a large chromatic bandwidth.
Therefore an object of embodiments of the invention is to provide a 380 nm to 900 nm apochromatic micro-objective which has a numerical aperture from 0.36 to 0.4 and an object field of 4.4 mm and which exhibits a sufficiently good transparency up to a wavelength of 340 nm.
According to embodiments of the invention, the microscope objective comprises three optical sub-systems, wherein starting from the object plane                the first sub-system includes a meniscus and a convergent lens, wherein the meniscus is curved towards the object plane,        the second sub-system is made up of three elements, wherein a first element consists of a meniscus or a cemented element,        a second element is configured as a collecting cemented element and        a third element includes a cemented element,        wherein either the first element or the third element is designed to be strongly scattering and        the third sub-system has at least one cemented element with a collecting lens.The convergent lens of the first sub-system is advantageously made of a Fluorkron glass.        
Furthermore it is advantageous if the first element of the second sub-system as meniscus is made of a highly refractive lanthanum glass or of a cemented element having at least one lens made of a short flint glass.
The second element of the second sub-system advantageously consists of a convergent lens made of Fluorkron glass or CaF2 and a diverging lens made of a highly refractive lanthanum or short flint glass.
Likewise it is advantageous that the cemented element of the third element of the second sub-system has a lens made of a lanthanum glass and a convergent lens of the third sub-system is made of Fluorkron glass or CaF2.